This file is (unfortunately) mixed up. The deceased is named "Burness Bruce," not "Bruce Burness" and is a female. The listing is wrong on NamUs and the Spokane County Medical Examiner's Unclaimed Remains page (link here), and then reported incorrectly by The Spokesman-Review (link here).

"United States Social Security Death Index," Burness O Bruce, 1999
first name: Burness
middle name: O
last name: Bruce
name suffix:
birth date: 26 May 1909
social security number: 534-46-5119
place of issuance: Washington
last residence: Spokane, Washington
zip code of last residence: 99223
death date: 11 December 1999
estimated age at death: 90

Ms. Bruce is listed as an "inmate" in the 1940 census. I have found mentions of a State Custodial School in Espanola Township - Spokane in the 1930s and an Eastern State Hospital in Espanola Township - Spokane as well as references to an asylum. It sounds like she was institutionalized at the time of the census.

It looks like Burness Bruce had a twin named Beaurl. The family tree listed four children for Beaurl. I found an obituary for his wife who passed in 2011 listing the same four children and spouses (link here). I think I have found the contact information for the daughter of one of these children - who would be Burness Bruce's grand-niece. PM'ing the information to Raine and Nemo'sMom!